The present disclosure relates to power filter circuits, and more specifically, to integration of an inductor and damper for a power filter circuit.
A basic building block of a power filter is a low pass filter including an inductor (L) and a capacitor (C). This filter can also contain a damper circuit including a capacitor and a damper resistor (R). Prior art damper resistors use off-the-shelf resistors that may be either thick film or metal foil resistors. Resistor failures have been the leading cause for failures of various motor controllers during production process. The prime causes of the resistor failures are due to fragile ceramic base and low pulse power capability of the resistor element.
Conventional wire wound resistors are generally large and bulky. The package style would require wire harness and supports that increase the production time and cost significantly, and also reduce overall reliability. It may be advantageous to integrate the resistor into the filter inductor package without changing its size. By integrating the resistor into inductor package the printed wiring assembly, component count and factory assembly time can be reduced, and the pulse power capability can also be increased by several order of magnitude hence improved reliability.